Plant Community Composition and Structure of Asabot Dry

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DOI: 10.4172/2332-2543.1000202

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J Biodiversity & Endangered Species

Research Article Open Access Plant Community Composition and Structure of Asabot Dry Afromontane Forest, West Harare Zone, Ethiopia Tura TT*, Soromessa T, Leta S and Argaw M Center for Environmental science, Addis Ababa University, Ethiopia

Abstract Dry Afromontane forests are the most altered and threatened ecosystem. Indeed, having a diverse ecosystem and biodiversity designated as a priority site in conservation. The objective of this study was to demonstrate plant community structure, regeneration status, and conservation priority species. The study was conducted on Asabot mountain forest which is found in West Harare Zone, Oromia National Regional State, Ethiopia. The vegetation sampling was designed at clustered altitude through mixed spatial stratified-random sampling method to ensure a full coverage of environmental variation and habitat heterogeneity. The main parameters used in vegetation characterization was diameter at breast height (DBH), height, seedling, and sapling of wood species recorded at sampled quadrat. The study analyzed plant community indicator species, importance value index, and vegetation structure and regeneration status, and conservation priority of selected species. The plant community was described by 97 species of 90 genera and 52 families. The result showed that eight specific trends and three general trends of population structure based on DBH, seedling, sapling and mature trees or shrubs. The dominant classes of the Asabot dry Afromontane forest were small trees and shrubs which is an indication of secondary vegetation. The conservation priority classification and visual field observations of some woody species were required urgent management intervention. Furthermore, the detail botanical aspects of the forest, the reason for the absence of regeneration in some tree species and socio-economic aspect of the vicinity is strongly recommended farther research in order to inaugurate appropriate management intervention.

Keywords: Dry afromontane forest; Plant community; Indicator present study intended to analyze plant community, forest structure, species; Structural analysis; Regeneration status and regeneration status of some woody species in order to forecast conservation priority and appropriate management. Introduction Methods and Materials The natural gifts of African countries with high endemism of animal and plant species passionate by Ethiopia diverse agroecology [1]. The Study site description agricultural extensive and excessive deforestation hampered natural Asabot mountain forest is located in Miso district of West Harare regeneration and seedling establishment that affected the diversity Zone, Oromia Regional state, Ethiopia (Figure 1). Geographically, the and structure of plant communities in most tropical forests [2-4]. In a study site is located at 40° 31’30 to 40° 42’0E and 9° 12’0 to 9° 21’0N. similarly way forests in Ethiopia in general and dry Afromontane, in The altitude of Asabot Mountain ranges from 1087 to 2474 meters above particular, have been affected by climatic and anthropogenic factors [5- sea level (Table 1). 9]. The assessment of forest cover change history of Ethiopia indicated reduction from 40% to less than 2.8% in the 19th century with current Asabot mountain forest is part of evergreen dry Afromontane improvement to 15% [10,11]. The shifted vegetation shared half by ecology; characterized by average minimum (451.2 ml) and maximum Afromontane forest or mostly by dry Afromontane forests [1]. The (1055.5 ml) annual precipitation, mean minimum (11.9°C) and maximum (31.9°C) temperature, respectively according to metrological climatic characterization of Afromontane in Ethiopia distinguished by data for the last ten years (Figure 2). moisture than surrounding lowland [12,13]. The agroecology of dry Afromontane is described by an altitude range from 1500-3400 m above The topography of the study site was raged mountain characterized sea level; 700-1100 mm mean annual rainfall; and 14-25°C average by flat (1577 hectare) to rolling (803 hectares) (Table 1 and Figure 3). annual temperature with coverage of distributed highland of central, Asabot mountain ascends from 1080-2447 meter above sea level with northern, eastern and southern parts of Ethiopia [5,14,15]. This suitable immediate facing (aspect) change. However, the vegetation samples for human inhabitation accompanied by sedentary agriculture, extensive collected from an altitude range of 1778 to 2404 meter above sea level in cattle herding activities and socio-political instability. Dry Afromontane order to reduce edge effects and due to the scope of the study. ecology exposed to heavy deforestation, forest fragmentation and loss of biodiversity, impoverishment ecosystems and climate change vulnerability [16]. Indeed, they are a very important in-situ biodiversity *Corresponding author: Tura TT, Ph.D. fellow, Center for Environmental science, Addis Ababa University, Ethiopia, Tel: +251-111-239 472; E-mail: tulutollatura@ conservation spot [17]. In view, the study has been conducted valued on gmail.com addressing plant community variation along an environmental gradient Received October 30, 2017; Accepted December 05, 2017; Published December of Asabot mountain forest. 10, 2017 Though the current progress made on Asabot mountain forest Citation: Tura TT, Soromessa T, Leta S, Argaw M (2017) Plant Community demarcation as national wildlife protection sanctuary, the forest Composition and Structure of Asabot Dry Afromontane Forest, West Harare Zone, Ethiopia. J Biodivers Endanger Species 5: 202. doi: 10.4172/2332-2543.1000202 is currently continuously exploited by surrounding people for construction woodcutting, timber harvesting, charcoal production, Copyright: © 2017 Tura TT, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted firewood collection and other. Indeed, the plant community, floristic use, distribution, and reproduction in any medium, provided the original author and composition, and structure were not well studied yet. Therefore, the source are credited.

J Biodivers Endanger Species, an open access journal Volume 5 • Issue 4 • 1000202 ISSN: 2332-2543 Citation: Tura TT, Soromessa T, Leta S, Argaw M (2017) Plant Community Composition and Structure of Asabot Dry Afromontane Forest, West Harare Zone, Ethiopia. J Biodivers Endanger Species 5: 202. doi: 10.4172/2332-2543.1000202

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Sampling design slope not strictly followed. The 20 m × 20 m (400 2m ) size sampling quadrats of 150 m and 100 m distance between transect and quadrat, The vegetation sampling method was chosen the mixed spatial respectively used. Inside the 20 m × 20 m quadrat five, 5 m × 5 m stratified-random procedure to ensure a full coverage of environmental subplots, one at each corner and one at the center of the main quadrat variation and habitat heterogeneity within the altitudinal gradient were set to sample shrubs. The seedling and sapling data were collected following Kent and Coker [18] and Muller-DuBois and Eilenberg [19]. from five 2 m × 2 m subplots, one at each corner and one at the center The direction of sampling quadrats was not followed strict procedure of the main plot. The diameter of all woody plants was recorded using due to the complexity of the mountain. The quadrats covered clustered diameter tape while height was measured using Hagan hypsometer and altitude of the study sites (lower, middle and upper) but aspect and Clinometer. The diameter of normal individual trees was measured at

Figure 1: Map of Asabot dry Afromontane forest.

Altitude Area in ha Slope Area in ha Aspect Area in ha 1087--1200 494 0--2 1577 North 4617 1201--1400 3688 3--8 6644 East 4697 1401--1600 7726 9--15 2781 South 3417 1601--1800 2360 16--32 4710 West 3776 1801--2000 1270 33--59 803 North 4617 2001--2200 676 - - - - 2201--2474 297 - - - -

Table 1: Description of Asabot mountain forest.

Figure 2: Mean annual precipitation and mean annual maximum temperature trends of the study site, 2004-2015.

Page 3 of 12 breast height if the tree branched at breast height; and the diameter was image [18]. The specimens of all woody plant were pressed, dried and measured separately and averaged if the tree was multi-stemmed. The brought to the National Herbarium of Addis Ababa University for diameter was measured individual and recorded if the tree buttressed identification and storage. The wood plant nomenclature was followed at breast height. The diameter was also measured above or below the Flora of Ethiopia and Eritrea book (FEE). breast height at normal shape; and if the tree was angled or slopes, the diameter was measured opposite direction of the inclination (Figure 4). Plant community analysis Where topographic features made it difficult to measure trees and The dendrogram wood plant community cluster was analyzed based shrubs, height was estimated visually. The environmental variables such on cover abundance data of species composition in their hierarchical as altitude, slope, aspects and geographical coordinates were measured classification. The plant community types were named after two or three for each plots using Garmin Geographical Position System and satellite dominant species selected using the relative magnitude of their mean

Figure 3: Altitude, slope and aspect description of asabot mountain forest.

Figure 4: Sample plot distribution.

Page 4 of 12 cover abundance values. The synoptic table classification indicator selected species were also analyzed for the interpretation of the pattern species of plant community in each particular cluster were produced of population dynamics in the forest. using R statistical tool. Synoptic table produced from the summation Results and Discussions of Relative density (RD)+Relative dominance (RDO)+Relative frequency (R in percent. F) Results Importance value analysis Species composition: According to our sample, Asabot mountain The importance value indices (IVI) were computed for dominant forest was characterized by 103 species of 91 genera and 54 families. The trees species account for 26; shrubs species account for 36; lianas species woody species based on their relative density (RD), relative dominance account for 6 and 35 species were a woody hemi-parasite. Poaceae, (RDO) and relative frequency (RF) as researcher Kenta and Coker described [18]. Importance value index ( IVI)=Relative density Oleaceae, and Anacardiaceous were the most dominant families, contributing 12, 5 and 5 species to the total, respectively. These families (RD)+Relative dominance (RDO)+Relative frequency (RF), Where, were followed by Euphorbiaceous, Fabaceae, and Malvaceae which Relative density (RD)=(number of individual’s species diameter at breast height (DBH) >2.5 cm)/(total number of individuals’) × 100, contribute four species while the remaining 46 families contributed only three and fewer species. where, Relative dominance (RDO)=(Dominance of a species DBH>2.5 cm)/(Dominance of all species) × 100, where, Relative frequency Plant community: The plant community analysis was clustered (RF)=(Frequency of a species)/(Frequency of all species) × 100. under three classes based on relative abundance of the individual in However, the dominance is defined as the mean basal area per tree, their respective samples (Figure 5). The clustering Euclidean distance multiplied by the number of trees of the species. was named after two dominant species within the group following Structural data analysis Whittaker method [22]. The abundance value of each species indicates the given community dominant species. The majority of sample plots The DBH classes were analyzed based on the interval that class is, have similar plant community abundance and classified under cluster 1 stands for 1.0-2.50 cm, 2 stands for 2.51-10.0 cm, 3 stands for 10.01- one. Cluster 1 accounts for 54.14% sample plots; cluster 2 accounts 15.0 cm, 4 stands for 15.01-20.0 cm, 5 stands for 20.01-25 cm, 6 stands for 31.43% sample plots; and cluster 3 accounts for 11.43% sample for 25.01-30.0 cm, and 7 stands for >30.0 cm. In the similar way height plots. The synoptic table indicated that the indicator species for plant classes were analysed based on the intervals that class is1 stands for 2-5 community in cluster 1 were Olea europaea, Dodonea angustifolia, cm, class 2 stands for 5.01-8 cm, class 3 stands for 8.01-12 cm, class Pterolobium stellatum and Euclea racemose; cluster 2 plant community 4 stands for 12.01-15 cm, class 5 stands for 15.01-20 cm and class 6 indicator species were Jasminum abyssinicum, Cuppuresses lusitanica, for more than 20.00 cm. As literature states basal area importance in Maesa lanceolata, Rumex nepalensis and Terminalia catappa, and providing a better measurement of the relative importance of the species cluster 3 plant community indicator species were Teclea simplicifolia, than stem count [20], we analyzed basal area (BA) using a standard Podocarpus falcatus, Grewia sp., Myrsine africana and Acokanthera 2 equation based on diameter at breast height. BA=d π /4, where, BA is schimperi. These species considered as Asabot dry Afromontane basal area, π=3.14; d is DBH (m). The density of trees or shrubs and basal forest plant community indicator species and an illustration of species area values were computed using a number of individuals per hectare represents dry Afromontane forest ecology plant community if the and m2 per hectare, respectively. Furthermore, the vertical structure macro and micro environmental variables variability not triggered. of the woody species was analyzed using the IUFRO classification The plant community importance value index classes for each species scheme [21]. This scheme categorizes a vertical structure of vegetation showed an inverted J-shaped curve. That means most species in the first into upper, middle and lower story. The population structures of some IVI class and few species in the last IVI class (Figure 6).

Figure 5: Dendrogram representation of plant community in asabot dry afromontane forest.

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The synoptic table classification of plant community was represented also considered as Asabot dry Afromontane forest plant community indicator species in each cluster. Plant community indicator species in indicator species. Cluster 1 were Olea europea, Dodonea angustifolia, Pterolobium stellatum Importance value index (IVI): Cuppuresses lusitanica, Olea and Euclea racemosa, and cluster 2 plant community indicator species europaea, and Podocarpus falcatus species had the highest importance were Jasminum abyssinicum, Cuppuresses lusitanica, Maesa Lanceolata, value index (Table 3). This might be due to the contribution of endowed Rumex nepalensis and Terminalia catappa; cluster 3 plant community monastery community by protecting those high economic and cultural indicator species were Teclea simplicifolia, Podocarpus falcatus, Grewia sp., value species from the local intruders in demand of timber and other Myrsine africana and Acokanthera schimperi (Table 2). Those species were construction material. These three species contributed about 30.05% of the total importance values whereas the remaining woody species had Species Cluster 1 Cluster 2 Cluster 3 combined IVI of about 69.95% (Table 3). Species with lower IVI need Olea europaea 4.67 2.38 0.25 high conservation efforts while those with higher IVI need monitoring Dodonea angustifolia 3.56 3.46 0.00 and management. Pterolobium stellatum 3.34 1.46 0.25 Euclea racemosa 2.72 1.69 1.25 The study showed that most species have lower IVI classes whereas Jasminum abyssinicum 0.23 5.45 1.50 very few species have high IVI classes (Figure 6). Cuppuresses lusitanica 0.78 4.85 0.25 Tree and shrub density: The density of trees and shrubs with Maesa Lanceolata 0.17 3.31 0.00 DBH greater than 1 cm was 875.97 individuals ha-1. The density of Rumex nepalensis 0.06 3.23 0.00 trees and shrubs with DBH 10-20 cm was 137.5 individuals ha-1. The Terminalia catappa 1.00 2.85 0.00 density of trees and shrubs with DBH greater than 20 cm was 71.16 Teclea simplicifolia 0.06 1.54 16.25 individuals·ha-1 (Table 4). The ratio described as c /d, is taken as the Podocarpus falcatus 0.61 1.15 1.50 measure of size class distribution. Accordingly, the ratio of individuals Grewia.sp 0.00 1.46 1.50 with DBH 10.01-20 cm (c) to DBH >20 cm (d) was 1.93. Myrsine africana 0.44 1.00 1.50 Acokanthera schimperi 1.11 0.69 1.25 The comparison of tree and shrub densities in DBH class 10.01-20 (Refer Annex B for the entire species) cm (c), DBH class greater than 20 cm (d) and C/D ratio for Asabot Table 2: Synoptic table cover-abundance values of species having higher value mountain forest with eleven other forests in Ethiopia were given in Table 5. The ratio of DBH 10-20 cm to DBH>20 cm at Asabot mountain forest was lower than Chi limo, Dindin, and Masha Andaracha, Species RA RF RDO IVI Podocarpus falcatus 2.91 2.77 44.67 50.35 Menasha Suba, and Mena Angst forests but higher than Alata-Bolale, Cuppuresses lusitanica 1.05 2.65 25.38 33.35 Woof Washi, Kamtok, Kamtok, Guar Freda, Donor and Doodle Forests Olea europaea 1.25 4.94 10.86 18.94 (Table 5). Jasminum abyssinicum 5.09 4.05 0.94 8.12 DBH class distribution: The DBH class and wood species density Teclea simplicifolia 2.97 4.97 0.07 8.01 showed the irregular relationship. As DBH increased from first class Euclea racemosa 1.60 4.27 0.82 6.69 to second class, individual’s species number increased very high from Anchyranthus aspera 3.17 1.08 1.76 6.01 17.31stems ha-1 to 650 stems ha-1; then decreased and finally increased Psydrax schimperiana 1.74 4.21 0.04 5.99 relatively. The curve was showed an irregular distribution of individuals Olea welwitschii 1.32 1.92 2.54 5.79 across the DBH classes (Figure 7). Acokanthera schimperi 1.99 3.60 0.184 5.77 Dodonea angustifolia 1.64 2.78 1.28 5.56 Tree species were classified according to different DBH classes, such as 1 stands for 1.0-2.50 cm, 2 stands for 2.51-10.0 cm, 3 stands (Refer Annex C for the entire species) for 10.01-15.0 cm, 4 stands for 15.01-20.0 cm, 5 stands for 20.01-25 Table 3: Top ten species with high importance value index.

(IVI classes 1 stands for 1-5, class 2 stands for 5.1-10.0, class 3 stands for 10.1-15.0, class 4 stands for 15.1-20.0, class 5 stands for >20.0) Figure 6: Number of species in the importance value index class

Page 6 of 12 cm, 6 stands for 25.01-30.0 cm, and 7 stands for DBH>30.0 cm. The The basal area of Asabot mountain forest was less than that DBH class distribution showed that more than 76% of all individuals of Wotagisho forest [23], Alata-Bolale Forest [24], Menasha Suba, had DBH less than 10.01 cm (Table 6). Chilimo, and Denkoro Forests [25], Dindin Forests [26], Gendo Forest, Masha-Anderacha Forest [27], Jibat and Wof-Washa Forest [28]. Basal area: The mean total basal area of Asabot mountain forest is 22.45 m2 ha-1. The highest percentage of basal area (74.98%) contributed Height class distributions: The density of individual trees and by DBH class 7 (DBH>30.0 cm), however, the DBH class of the rest shrubs distribution along height classes of Asabot mountain forest were individual tree density was contributed only 25.02%. Conversely, showed decreasing as height increases (Figure 9). individuals in the DBH classes less than 30 cm had a density of about More than 88% of trees and shrubs were less than 8.01 m tall 95% of the total but accounted only 25.02% of the total basal area of the (Height classes 1 and 2). Only a small proportion, about 3.6%, reached forest (Table 7 and Figure 8). a height of 20.01 m and above. The study showed that shorter plants Species with the largest contribution in the basal area can were the dominant plant community (Table 7). be considered the most important woody species in the forest. Vertical structure: The vertical structure story of Asabot mountain Accordingly, descending order of some top tree species with the highest forest was classified using IUFRO classification scheme [21]. The basal area in Asabot mountain forest was Podocarpus falcatus, Juniperus maximum tree’s height in Asabot mountain forest was 40 m which are procera, Olea europaea, Olea welwitschii, Nicandra physaloides, Acacia comparable to another forest in Ethiopia. The main tree species that abyssinica, Dodonea angustifolia, and Teclea nobilis. classified under upper story wereJuniperus procera, Nicandra physaloides, Podocarpus falcatus, Euclea racemosa and Cassipourea malosana. When we -1 DBH (cm) No. of individuals (ha ) Percentage (%) compare each story based on the number of individual trees, the lower 1.0–2.5 17.31 2.0 story was higher than the upper story (Table 8). 2.51–10.0 650 74.2 10.1–20.0 137.5 15.7 Density Basal Area DBH Class >20.0 71.16 8.1 Number of Stems Percent (%) Area (m2) Percent (%) Total 875.97 100.0 Class 1 1.0 0-2.5 17.31 2.00 0.01 0.02 Table 4: Density of trees and shrubs by diameter at breast height class. Class 2 2.50-10 650.00 74.20 1.96 8.71 Class 3 10.01-15 90.38 10.30 1.11 4.95 Density ratio Class 4 15.01-20 47.12 5.40 1.06 4.74 Forests Source (c) (d) (c/d) Class 5 20.01-25 15.39 1.80 0.63 2.79 Woof Washi 329.00 215.00 1.53 Bekele, 1993 Class 6 25.01-30 13.46 1.50 0.87 3.81 Menasha Suba 484.00 208. 20 2.33 Bekele, 1993 Class 7 >30 42.31 4.80 16.83 74.98 Kamtok 330.00 215.00 1.53 Facade et al. 2012 Total 875.97 100.00 22.45 100.00 Doodle 521.00 351.00 1.48 Hund era et al. 2007 Table 6: DBH class, Density and Basal Area of tree and shrub of asabot mountain Donor 526.00 285.00 1.85 Azalea et al. 2006 evergreen natural forest. Guar Freda 500.00 263.00 1.90 Danu, 2006 Masha Andaracha 385.70 160.50 2.40 Yeshitela et al. 2003 Height Class Density Percent (%) Dindin 437.00 219.00 2.00 Shibru and Balcha, 2004 Class 1 2-5 512.5 58.50 Mena Angst 292.00 139.00 2.10 Lulekal, 2008 Class 2 5.01-8 260.58 29.70 Alata-Bolale 365.00 219.00 1.67 Woldeyohannes, 2008 Class 3 8.01-12 53.85 6.10 Chilimo 638.00 250.00 2.55 Bekele, 1994 Class 4 12.01-15 8.65 1.00 Asabot 137.50 71.16 1.93 Current study Class 5 15.01-20 8.65 1.00 Table 5: Comparisons of trees and shrubs density with DBH 10-20 cm (c) and tree Class 6 more than 20.00 31.73 3.60 density with DBH >20 cm (d) from Asabot mountain Forest with 11 other forests Total 875.97 100.0 in Ethiopia. Table 7: Height class, density, and percent of trees and shrubs in the study site.

Figure 7: DBH class versus the number of individuals per hectare.

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Figure 8: Basal Area distribution in percent across DBH class.

Figure 9: Tree and shrub individual density distribution along height class.

The middle layer vertical structure of Asabot mountain forest cluster structure. The mean Shannon diversity index of plants in was occupied by species including Capparis tomentosa, Cuppresus the study site was 1.61, Simpson diversity index was 4.83, Shannon lustanica, Podocarpus falcatus, Olea welwitschii, Bersama abyssinica, Evenness index was 0.72 and Simpson Evenness index was 0.74 (Table 10). Ficus Sur, and Olea europaea. However, the lower story was largely Relative abundance, relative frequency, and relative dominance: dominated by Acacia abyssinica, Acokanthera schimperi, Capparis Achyranthus aspera, Allium sp., Teclea simplicifolia, Celtis toka, Jasminum tomentosa, Clerodendrum myricoides, Dodonea angustifolia, Euclea abyssinicum, Myrsine africana, Pittosporum Veridiflorum, Grewia sp. racemosa, Pavetta abyssinica, Ozoroa insignis, Protea gaguedi, Psydrax and Podocarpus falcatus were the most abundant species, account for schimperiana, Rhus retinorrhoea, Schefflera abyssinica and Terminalia 25.24% of total density. Olea europaea, Teclea simplicifolia, Achyranthes sp. The majority of species were concentrated in the lower story aspera, Euclea racemosa, Psydrax schimperiana, Acokanthera schimperi (76.27%) followed by the middle (15.25%) and very lowest at the upper and Pterolobium were recorded highest frequency whereas Podocarpus story (8.48%) (Table 8). This showed a similar trend with Kamtok falcatus, Cuppuresses lusitanica and Olea europaea were recorded highest Afromontane moist forest [1] and Bonga Forest [29]. relative dominance. Olea europaea, Cuppuresses lusitanica and Dodonea Plant diversity: Plant diversity indicates healthiness and survival angustifolia were high relative frequency and high relative dominance capacity of ecology while unexpected environmental shocks happen. species whereas Podocarpus falcatus and Achyranthus aspera were both Species richness highest at cluster 1 (41.91%) and lowest at cluster 3 high relative abundance and high relative dominance species. Indeed, (18.38%). The Shannon diversity, Simpson diversity, Shannon Evenness Teclea simplicifolia was the only plant species with both high relative and Simpson Evenness were highest at cluster 2 and lowest in cluster 3 abundance and relative frequency in the study site (Table 11). (Table 9). Indeed, the study showed that high species richness not an Population structure: The pattern of diameter class distribution indication of diversity and evenness. indicates general trends of population dynamics and recruitment The entire study site plant community structure was similar with processes of each species. Indeed, the analysis of population structure

Page 8 of 12 for 27 species revealed eight specific and three general patterns (Figure external intruders. But most of these species not dominate in another 10). The total seedling, sapling, and mature woody tree densities of 27 forest due to high market demand [1,33]. The study showed few plants selected species were about 1268, 231, and 911 individuals per hectare, contributed a large share of the total basal area confirming similar respectively (Table 12). The structural analysis indicated the majority studies in Ethiopia [1,27,30,33]. of plant community found in the DBH class 10 cm to 20 cm and the The population of 27 selected tree species showed eight more value less than most available studies in Ethiopia. But the ratio of specific and three general patterns based on DBH class of their medium (DBH class 10 to 20 cm) and large (DBH class >20 cm) was abundance (Figure 9). Plant species represented their populations in greater than Woof Washi [28], Kamtok [1], Doodle [30], Donor [25], particular pattern were Olea europaea, Dodonea angustifolia, Protea Guar Freda [31], and Alata-Bolale [24] forests. The ration of medium gaguedi, Acacia abyssinica, Juniperus procera, Podocarpus falcatus, Olea and large classes was lower than Menasha Suba [28], Chilimo [13] welwitschii and Conyza hypoleuca. Most of the pattern showed higher and Masha Anderacha [27], Mena Angst [32] and Dindin [26]. The density in lower DBH classes which suggesting good reproduction and plant community structure of Asabot dry Afromontane forest mainly healthy regeneration potential. The other pattern showed the lowest represents by the two DBH classes if the microscale environmental density in the lower classes which is a sign of poor reproduction and variables variability not triggered. recruitment. The other populations were represented by the irregular The DBH and height class distribution indicated an inverted pattern. This result showed a similar trend with other studies in J-shaped curve with most individuals in the lower size classes (Figures 7 Ethiopia [1,24,34]. Most of the plant population in Asabot mountain and 8). However, the basal area class distribution of individuals showed forest was in a deficiency of intermediate DBH classes which might be J-shape. The DBH and height class distribution demonstrated a high due to selective removal of medium-sized wood plants. This might be rate of regeneration but the minimum number of tree density in the due to Asabot mountain forest is the only natural forest in the vicinity higher DBH and height class distribution might be due to the high rate currently under pressure of local intruders. In our observation, the of selective tinning. This agreed with studies conducted different parts main reasons for the absence of medium DBH classes were selective of the country [1,33]. The total basal area of woody plant community tinning for construction, timber and firewood. 2 -1 in the sample plots of Asabot forest was 22.44 m ha . The highest Regeneration status of asabot mountain forest: The composition, basal area was contributed by Podocarpus falcatus, Juniperus procera, distribution and density of seedlings and saplings are an indicator for Olea welwitschii and Olea europaea. The predominance of these species the future habitat conditions, geographical distribution, composition, in the forest was probably because of their spiritual significance and successful regeneration and survival and growth of forests within space Asabot monastery community role in the management of forest from and time [35-38]. The distribution of seedlings, saplings and mature

Stems Species Story Height (m) Class Ratio of individuals to species Density Percentage (%) No. Percentage (%) Lower 2-13.33 826.93 94.4 45 76.27 18.38 Middle 13.3326.66 16 1.83 5 8.48 3.2 (The story of trees classified into upper, where the tree height is greater than 2/3 of the top height; middle, where the tree height is in between 1/3 and 2/3 of the top height; and the lower story, where the tree height is less than 1/3 of the top height) Table 8: The vertical structure story of trees in the Asabot mountain forest.

Cluster Richness Shannon diversity Simpson diversity Shannon Evenness Simpson Evenness Cluster 1 57 3.37 20.37 0.83 0.36 Cluster 2 54 3.86 42.79 0.97 0.79 Cluster 3 25 2.30 4.32 0.71 0.17

Table 9: Species richness, Shannon diversity index (H), Simpson diversity index, Shannon Evenness index (j) and Simpson Evenness index of each cluster.

Berger Parker Brillouin Chao D Equitability Evenness Fisher alpha Individuals Margalef Menhinick H Simpson Taxa 0.38 1.67 10.44 0.26 0.82 0.72 3.51 33.13 1.91 1.37 1.61 4.83 7.48

Table 10: Shannon Diversity index (H), Berger Parker, Brillouin, Chao, Dominance (D), Equitability, Evenness, Fisher alpha, Individuals, Margalef, Menhinick, H, Simpson, and Taxa.

Species RA Species RF Species RDO Achyranthus aspera 5.81 Teclea simplicifolia 4.97 Podocarpus falcatus 44.67 Allium spalhaceum 3.18 Olea europaea 4.94 Cuppuresses lusitanica 25.38 Teclea simplicifolia 2.97 Euclea racemosa 4.27 Olea europaea 10.86 Celtis toka 2.64 Psydrax schimperiana 4.21 Olea welwitschii 2.54 Jasminum Abyssinicum 2.37 Acokanthera schimperi 3.6 Achyranthus aspera 1.76 Myrsine africana 2.12 Pavetta abyssinica 3.01 Acacia abyssinica 1.591 Pittosporum Veridiflorum 2.08 Dodonea angustifolia 2.78 Protea gaguedi 1.38 Grewia.sp 2.05 Juniperus procera 2.71 Dodonea angustifolia 1.28 Podocarpus falcatus 2.02 Cuppuresses lusitanica 2.65 Nicandra physalodes 1.2

Table 11: Selected high relatively abundant, relatively dominant and relatively frequent species.

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Figure 10: Population structure of selected tree species (Tree species were classified according to different DBH classes, such as, 1 stands for 2.6-12.0 cm DBH, 2 stands for 12.1-22.0 cm DBH, 3 stands for 22.1-32.0 cm DBH, 4 stands for 32.1-42.0 cm DBH, 5 stands for 42.1-52.0 cm DBH, 6 stands for 52.1-62.0 cm DBH, 7 stands for >62.0cm DBH).

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Figure 11: Trees/shrubs, saplings and seedlings distribution of some selected species of asabot forest.

trees/shrubs show eight distinct patterns and three general patterns Plant species under conservation priority of class 1 and 2 might (Figure 11). be due to human and cattle disturbance, grazing and browsing, seed predation, and the need of dormancy period for seeds of certain trees Seven species (19.44%) were not represented by both seedlings which causes insufficient seedlings and saplings. In addition, Facade and saplings, and only a few mature individuals were recorded for and Coworker explained this phenomenon: litter accumulation, these species. On the other hand, five species (13.88%) of the total pathogens, moisture stress, and possession of alternative adaptations were not represented by saplings (Table 12). Accordingly, plant species for propagation other than seed germination could also be the cause for lack of sufficient seedlings [1]. This study showed a similar result with were grouped into three conservation priority classes; Class 1 with no Gurmessa, et al. [1], Danu [31] and Simon and Grima [26]. Indeed, our seedlings or saplings, Class 2 with seedlings but no saplings, and Class 3 study showed plant species under conservation priority 1 and 2 might with both seedlings and saplings greater than 1 individual’s ha-1 (Table 13). be under threat of local extinction and needs due attention.

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Scientific name Trees and shrubs Saplings Seedling Sum of densities Olea europaea 102 12 91 205 Acokanthera schimperi 25 6 16 47 Euclea racemosa 73 6 51 130 Psydrax schimperiana 8 17 43 68 Dodonea angustifolia 88 59 272 419 Carissa spinarum 24 30 88 142 Rhus retinorrhoea 49 7 73 129 Protea gaguedi 16 0 3 19 Acacia abyssinica 16 0 6 22 Maytenus spp. 13 4 24 41 Ozoroa insignis 2 0 90 92 Juniperus procera 70 22 30 122 Terminalia catappa 23 8 17 48 Bersama abyssinica 2 0 4 6 Capparis tomentosa 3 4 2 9 Myrsine africana 13 39 436 488 Clerodendrum myricoides 1 0 2 3 Acacia sp. 9 0 2 11 Sideroxylon oxyacanthum 1 0 3 4 Cassipourea malosana 2 1 3 6 Podocarpus falcatus 21 0 1 22 Croton macrostachyus 1 0 0 1 Calpurnia aurea 7 2 14 23 Schefflera abyssinica 10 8 13 31 Euphorbia tirucalli 4 3 2 9 Ficus Sur 3 0 0 3

Table 12: Selected tree species with their seedling, sapling and mature tree density per hectare.

Class 1 Class 2 Class 3 regeneration forest type. The density of woody species inversely related Croton with DBH and height classes implying good regeneration of the forest. Podocarpus falcatus Calpurnia aurea macrostachyus The basal area of Asabot dry Afromontane forest covered by very few Ficus Sur Sideroxylon oxyacanthum Schefflera abyssinica large plants while the majority contributed very small basal area. The - Clerodendrum myricoides Cassipourea malosana population structure of Asabot mountain forest described by different - Acacia sp. Capparis tomentosa patterns indicates high variation among species in population dynamics - Bersama abyssinica Fresen. Myrsine africana within the forest. The regeneration status analysis also showed that two - Ozoroa insignis Acokanthera schimperi species had no seedlings and saplings; seven species had no seedlings - Protea gaguedi. Juniperus procera or saplings; and the rest species were represented by seedlings, saplings - Acacia abyssinica Terminalia catappa and trees or shrubs. The woody species of the Asabot dry Afromontane - - Maytenus spp. forest was classified into three priority classes for conservation based - - Rhus retinorrhoea on their regeneration status giving due attention for first priority - - Olea europaea class as threatened species. Indeed, Asabot dry Afromontane forest is - - Acokanthera schimperi the only natural forest in the vicinity with high economic, social and - - Euclea racemosa political values for the local rural communities as a source of timber and non-timber forest products and ecosystem services for the lowland - - Psydrax schimperiana community. Indeed, the present multi-dimensional human influence - - Dodonea angustifolia on the natural forest needs urgent management strategy. Therefore, the - - Carissa spinarum first and the second priority class species should be given appropriate - - Rhus retinorrhoea attention by all stakeholders. Furthermore, extensive research is needed Table 13: Species conservation priority classes. to identify the reasons for the absence of regeneration in some species. In order to sustain forests, the vicinity participatory forest management Conclusion and Recommendation programs should be introduced and implemented by sharing the responsibility of management and conservation with the local The plant community in the study site within sampling quadrats was community through awareness creation and food security program. accounted for 103 species of 91 genera and 54 families. Dendrogram Finally, further investigation on the patterns of ecosystem functioning, clustering of plant community based on their abundance was found more socioeconomic and political environment in the vicinity should be than 55% sample plots under similar class. The synoptic table which studied for sustainable intervention. showed Olea europaea, Jasminum abyssinicum and Teclea simplicifolia was indicator species for their respective clusters and the study site. This References illustrated Asabot dry Afromontane forest similar plant community 1. Gurmessa F, Soromessa T, Kelbessa E (2012) Structure and regeneration abundance along the environmental gradient and structurally described status of Kamtok Afromontane moist forest, East Wollega Zone, west Ethiopia. by small trees and shrubs predominance was an indication of secondary J For Res 23: 205-216.

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J Biodivers Endanger Species, an open access journal Volume 5 • Issue 4 • 1000202 ISSN: 2332-2543